CHICAGO — For years, millions of Americans have spent billions of dollars on alternative remedies with unproven effects. Now, rigorous science is starting to test those treatments and mostly finds them lacking.

Last week, major government-funded research indicated that two wildly popular arthritis pills, glucosamine and chondroitin, did no better than dummy pills at relieving mild arthritis pain.

Earlier this month a study revealed negative results for saw palmetto to treat prostate problems; last July, ditto for echinacea and the common cold. Those followed similar disappointments for St. John’s wort to treat major depression, and powdered shark cartilage for some cancers.

Yet despite the U.S. government’s multimillion-dollar investment to scientifically scrutinize a little regulated $20 billion-a-year industry, the big question is, do the results really matter when so many consumers swear by these remedies?

“I’ll wrestle anybody who says it’s no good,” Carl Haupt, 79, says of glucosamine and chondroitin, pills he credits with helping him resume mountain hiking, a hobby he quit seven years ago because of arthritis pain.

Haupt spends about $25 monthly on the pills. Debilitating pain returned when he quit taking them once, and he said the government’s results won’t change his mind.

Even the researchers themselves, funded by the National Institutes of Health, say their results don’t necessarily mean consumers are pouring their money down the drain.

“If someone tells me this is working for them, I’m not going to tell them not to take it,” said Dr. Thomas Schnitzer, a Northwestern University arthritis specialist and co-author of the glucosamine/chondroitin study.

That’s partly because the three most recent studies found no real harm; also, in some cases, the results are not completely clear-cut.

For example, while most people taking the arthritis pills in the study got no significant benefit, the pills did appear to help those with more severe pain. And critics of the echinacea study say different doses might have found a benefit in fighting colds.

Also, studying these herbs and extracts is far more challenging than researching prescription drugs, which are subject to Food and Drug Administration scrutiny. Alternative health products with the same name can have vastly different ingredients and potencies, and research results from one may not apply to others, said Gail Mahady, a botanicals researcher at the University of Illinois at Chicago. She was not involved in the federal studies.

'Wishful thinking' worksBut another important factor is what scientists call the placebo effect — meaning that just thinking you’re taking something useful can make you think there’s a benefit.

Imaging tests have shown changes in the brains of placebo users, suggesting that the effect is not just “in your mind,” it’s also in the brain, said Dr. Stephen Straus, director of NIH’s National Center for Complementary and Alternative Medicine.

“Their wishful thinking that they’re going to get better is harnessing the body’s own mechanism for relieving pain,” said Straus, whose agency was formed seven years ago to stringently test non-conventional remedies.

The placebo effect was huge in patients unknowingly taking dummy pills in the arthritis study and could have overshadowed any potential benefit from the real pills.

But it’s also likely that the placebo effect contributes to benefits that many people say they get from alternative remedies, and it’s something doctors shouldn’t dismiss, said Dr. Anthony Miksanek, a family physician in rural southern Illinois who has many arthritis patients on glucosamine and chondroitin.

“My thought is if you give somebody a pill and say this may help you,” that might be the spark they need to “get out and do more things, walk more,” or get more exercise, all of which can help relieve arthritis pain, said Miksanek, of Benton, Ill.

“Maybe it’s a message of hope ... and the brain kind of takes that and runs with it,” he said.

Milly Navarro, a 33-year-old public relations specialist in Dallas, said she doesn’t care if the placebo effect explains why echinacea keeps her from getting colds — she’ll keep taking it anyway.

“I know the mind is a powerful thing and even if it’s that that does the trick, whatever it is, it works for me,” Navarro said.

Barrie Cassileth, an alternative medicine researcher at Memorial Sloan-Kettering Cancer Center in New York, said some products, including echinacea and St. John’s wort, can interfere with conventional medicine and should not be considered harmless.

But others, including saw palmetto, are cheaper and have fewer side effects than prescription medicine. “If the results that people swear by work by placebo, who cares?” she asks.

Rates of women who are opting for preventive mastectomies, such as Angeline Jolie, have increased by an estimated 50 percent in recent years, experts say. But many doctors are puzzled because the operation doesn't carry a 100 percent guarantee, it's major surgery -- and women have other options, from a once-a-day pill to careful monitoring.

Ben Pratt, a spokesman for the General Nutrition Centers, a national chain of stores that sell nutritional supplements, said sales of echinacea remain strong and were not affected by last summer’s negative study.

Some consumers use alternative medicine because of safety concerns about prescription drugs, including reports of heart problems that doomed the once-popular arthritis drug Vioxx. Others mistrust the medical establishment because it bombards them with contradictory studies.

“You can just wait long enough and someone else will have an opposite opinion,” said Richard Peterson, 62, a Baltimore property manager who says he won’t stop taking glucosamine.

But even if some consumers ignore the results, the rigorous government studies are extremely useful for doctors seeking to rely on more than word of mouth, said Miksanek, the family physician in Benton, Ill.

“We are very much relying now on evidence-based medicine,” said Miksanek. “We’re trying to get away from things like Doc Welby saying, ’I’ve used snake oil for years and it’s the greatest thing around.”’

Miksanek said now he can tell patients with minor arthritis pain that the pills may not work for everybody while offering more hopeful advice to patients with more severe pain.

Straus, of the NIH’s alternative medicine center, says his agency is committed to continuing research on supplements. The center’s research budget has steadily grown to $107.7 million for fiscal year 2005.

“I think that consumers should pay attention,” Straus said, “understanding that a single study may not provide the final answer.”